Used Car Catastrophe - Constant Problems

Hi everyone, I seem to have ended up with a disaster of a used car. Sparing the long story of how we ended up with the car, we didn’t pay a lot for it and my friend who didn’t know much about cars conducted the deal. Unfortunately the car is a mess.

For context, we have bought this car for the specific purpose of a trip abroad and then scrapping it at the end or reselling. We are in a region with very poor quality gas. My assessment is the car was very poorly maintained, example being it is missing a cabin air filter and they just duct taped over the hole where it should have been…

The car is a 2000 subaru forester. 182k miles.

What’s the problem?
Acceleration is extremely poor, the car crawls along the street at a low RPM until it eventually rises above 1000, and then it experiences a power surge and functions mostly normally. Sometimes it will go up to 4000/5000 rpm or more before it shifts out of first. Pinging in the engine and under the car has been attributed by various individuals to the bad gas here. (We had to put octane 80 in at one point… and I doubt it was actually 80). Turning off the AC helps the car reach a usable rpm faster.

Very rough idle and stalling at low speeds.

The car overheats while going up mountains/hills.

The coolant is brown, but we have been told it doesn’t have oil in it by a mechanic and by our own smell tests etc.

Check engine light comes on intermittently. (New symptom)

What has been tried?
Knock sensor replaced.
Spark plugs replaced.
Fuel pump replaced.
Fuel filter “cleaned”
Fuel injectors cleaned.
Battery replaced.
Engine air filter cleaned.

We’ve been told we need new spark plug wires and to flush the coolant out, but haven’t been able to find a shop yet that has the correct parts. No one works on subaru where we currently are, but in 2 days we will be able to go to someone that does.

Please, we are at a complete loss here. Is this car just dead or have we missed something? Is there any tests we can do ourselves to try to fix any of these problems?

The first thing to do is a compression yest to see if this engine is worth repairing. Subarus, especially high mileage ones are notorious for failed head gaskets.
When buying a car to drive in a foreign country, buy whatever is popular there.

It sounds like you have plain water in the cooling system. If the head gaskets are ok, change to a proper coolant.

Or think about selling this for whatever you can get for it.


Will attempt to get a compression test done, thank you for suggestion.

Subarus are quite popular in everywhere we’re going except this place… Chevy is king in Uzbekistan. Also LPG.

Look very closely at the temp gauge.

Do you see this?



Welcome to the forum…

Do you have a CEL (check engine light) on?? If so what are the codes…

I bet if you looked at live data your ignition timing is way retarded…
Try running an Octane booster… If you are truly running very low octane gas with a DIS (distributorless ignition system) then the computer adjust the ignition timing according to what the knock sensor is telling the ecm, the knock sensor picks up engine knock (preignition/detonation) and the ecm adjust the timing accordingly… If the engine is designed to run on 87 octane with a preset static ignition timing, then the ecm will adjust the dynamic ignition timing by advancing the timing until it picks up preignition then retard (pull timing out) until no more knock is present for best fuel economy and performance… The higher the octane number, the more resistant the gasoline mixture is to knock, so the lower the octane rating (number) the lower the resistance to engine knock, meaning the lower the octane the less timing you can run or your timing is being retarded to prevent engine knock/pinging/detonation/spark knock/preignition/whatever you chose to call it…

Also you generally run a much lower/base/static (retarded) ignition timing at adle and low rpms then at higher rpms (timing curve, rpms go up and the timing is advanced), so that could be your so called “power surge”, the ecm is advancing the timing more to get you moving but with the poor octane gas you are getting the pinging… On an older engine with a mechanical distributor, you have weights with springs that when the distributor rotates/spins the weights trying to overcome the spring tension by slinging outward to advance the timing as well as a vacuum advance that works off of engine vacuum… you can change out the weights and or springs to make that happen faster or slower depending on your engine combo and vehicle (more of a racer thing), some even lock out the distributor and set the timing at the engines desired full advance, again a racing thing…
If you had an engine with a distributor then you could adjust the ignition timing yourself, but when having a DIS the computer does all the adjusting for you with all the different sensor readings and makes the adjustments accordingly…

Yes there are other factors that determine an engines ignition timing but I am mainly talking about the affects of octane…

So if the head gaskets are good and the compression is good then I would be looking at adding some octane boost to any engine if the gas is really that bad/poor…

Not saying this is your total issue, but it can defiantly be a part of your running issues…

BTW timing that is retarded to much can/will reduce engine power and can cause other issues including overheating…

Hello and thank you for the welcome!

I’ve tried hooking my OBDII scanner to the car but it fails to link. Some small research suggests that the Netherlands model of these cars did not have OBDII until 2002 or so. When a mechanic scanned it the last time it was on, he told us it was Code 22 - Knock sensor (we replaced it, light went off).

That said, the CEL comes on intermittently now, we can’t pinpoint specific conditions. It’s unfortunate my OBDII scanner doesn’t do anything on this car…

We’re gonna take it to a shop tomorrow to try and setup a compression test.

Octane booster (if we can get our hands on it) we’ll try too.

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Is it possible to get better gas? Every other car you ever have driven has been ok even with your poor gas? It’s a 23 yr old car. How has it lasted this long? Is it new to the area?

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It is new to this area, yes. It is originally from the netherlands and drove to where it is now fine from my understanding. I can’t really say how it’s survived this long other than it probably had decent quality gas in the netherlands and the original owner treated it decently, the previous owners not so much.

I am now in a different country (I’m traveling around) which supposedly has better gas, we will fill it tomorrow. In Kazakhstan the gas was good and the car performed fine, minus overheating up hills, but when we filled it in uzbekistan we started having problems.

Tomorrow also we will try to get the compression test done.

coolant flush is important, but don’t waste your time or money doing that until it is running better. This is not the cause of your issue.

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This worries me. If the knock sensor wasn’t working and low-octane gas was being used, it seems like engine damage from knocking is likely.

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Engine reputation and overheating symptom point to a failed head gasket. Ask shop to test for that, pressure test cooling system, etc. If that’s the problem ask shop to replace the failed gasket, flush out the gunk in cooling system, replace thermostat, with any luck it might be running fine after that.

When the check engine light turns on, make sure to get the diagnostic code(s) read, and post them here. Intermittent check engine light are often due to evap system problems. Most evap system problem have little to no effect on engine performance. But a faulty purge valve can cause weird engine symptoms. If purge valve is the problem, there should be a corresponding diagnostic code stored in computer memory. (Powertrain diagnostic codes , like for engine problems, are in this format “Pxxxx”, like P0300 means misfires are detected. Make sure to post all p-codes.)

Worthwhile doing the test , but I’m guessing engine compression is not the problem.

Suggest next time you purchase a used car, hire your own mechanic to do a pre-purchase inspection. Money well spent.

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It’s a mechanical throttle body. What happens when you floor it while going slowly and it is running badly? Does it stall? Is the air filter very dirty?

Have the oxygen sensor been replaced with a good quality one?

How is the fuel pressure? How about the fuel filter? Those areas may have very dirty fuel. The momentary CEL might be a mixture too lean fault. A lean mixture can cause pinging or knocking. It also creates more heat which can damage valves and cause over heating.

Pre-ignition can’t be prevented by an anti-knock sensor. You have to use octane booster, or modify the engine to lower the compression, or stay away from full throttle and keep RPMs high.

Engine air filter is relatively clean. If you floor it when it’s doing badly it continues to limp along until you either turn off the AC or it just decides it’s time to drive at which point the cars rpm will creep upward until about 1000-1500. Once it reaches that there will usually be a pop/ping then it will rapidly increase in RPM and speed.

Oxygen sensor has not been replaced.

Fuel pressure was tested at the last shop and judged to be poor so they replaced the pump and attempted to clean out the filter since they didn’t have a replacement one. The stuff coming out of the filter was black. They advised we replace it when we find the part.

Would the purge valve being fault cause the CEL to stay on? It just comes on and off while driving. Not like a misfire where it would blink.

Would the compression test reveal a head gasket issue?

You have YouTube channel? Then people could follow your trip

If CEL blinks, that means you should stop driving and turn off the engine asap. Otherwise risk expensive damage. If it turns on and stays on, ask your shop to read the diagnostic codes. If it turns on, then turns off, and it is off at the shop, ask them if they have the ability to read the “history” section of the diagnostic codes. When the CEL turns on a diagnostic code is stored in the “current” section; but if the CEL later turns off , the current codes usually aren’t erased, they are moved to the history section. (There’s a “pending” section too, just to make things more complicated) . A problematic purge valve could turn the CEL on and it would stay on, or it could turn it on, then later it could go out. In the first case, that would likely mean the purge valve is allowing gasoline fumes into the engine when it shouldn’t. For the second, most likely the purge valve is malfunctioning and that is confusing the computer when it tests for air-tightness in the evap system. During the air-tightness test, the purge valve must be completely closed.

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It does on OBDII cars. The requirements for pre OBD II cars to self diagnose or store codes for emissions compliance problems is much less. Pre OBD II is not even required to test for EVAP system faults, nor catalyist faults, nor misfires. They will for oxygen sensor and I assume that’s a requirement.

Yes! That’s what the test is for. Either that or to test for a worn out engine or a bad valve.

Older cars don’t blink the CEL during misfires. The CEL is probably on due to a momentary condition such as misfires or a mixture too lean or rich condition.

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OP’s question is a yes and no answer…

A compression test reveals the condition of your engine’s valves, its valve seats, and piston rings etc and whether these parts are wearing evenly, but it can be an indicator of other internal problems such as a blown head gasket, but that doesn’t mean it is a blown head gasket as it could be a hole in the piston, part of the valve broken off and if you find 2 cylinders side by side with very low compression then that is a good indication of a blown head gasket that has blown between the 2 cylinders…
But an engine can blow a head gasket 6 different ways and only 3 of those are compression related…


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Check engine light was not on today when we went to the mechanic and he didn’t find anything stored on it.

He diagnoses the issue as bad spark plug wires and ignition coil and those were replaced.

During a test drive the vehicle performs entirely as normal, prior to the faults beginning.

Also had him flush the coolant out and replace the radiator cap.

Not sure if overheating will continue while going uphill but i’m going to test that when we get out of the city tomorrow.

also: No youtube channel at this time sadly!

20yr old Subarus are fine.